feat(dev-fkeys): add project-aware F4 compile/run dispatcher

I added a new module `modules/dev-fkeys.el` that owns the dev F-key block. F4 prompts via `completing-read` with a candidate set filtered by project type (compiled / interpreted / unknown). C-F4 is the compile-only fast path. M-F4 is clean + rebuild. It runs a heuristic clean command derived from the project markers (go.mod, Cargo.toml, Eask, Makefile, CMakeLists.txt) and chains `projectile-compile-project` on success. S-F4 stays on `recompile` and now lives globally instead of duplicated across prog-general.el and prog-c.el. F6 is bound globally to `projectile-test-project` as a Phase 1 stopgap. Phase 2 replaces it with the polyglot test runner spec'd in todo.org.

Project-type detection runs against the projectile root and falls back to `unknown` when no marker matches. Interpreted markers are checked first so a Python or Node project with a Makefile for tasks classifies as interpreted instead of compiled. Compile + Run sequencing uses a one-shot `compilation-finish-functions` hook that self-removes on first invocation and only fires the follow-up when the status string starts with `finished`.

Cleanup in the same commit:
- Dropped F4/F5/F6 from `prog-general.el`'s prog-mode-hook. They are now global.
- Dropped F6→format bindings from prog-c.el / prog-python.el / prog-shell.el. C-; f was already bound in each, so this is pure removal.
- Dropped the duplicate S-F4 from prog-c.el. The global binding covers it.
- Updated the keybinding header in prog-general.el and the workflow comments in prog-c.el / prog-shell.el.
- Wired `(require 'dev-fkeys)` in init.el alongside coverage-core.

TDD: 73 tests across 11 files, one per helper. Production code is split into small testable internals (`cj/--detect-project-type`, `cj/--f4-candidates`, `cj/--f4-derive-clean-cmd`, `cj/--f4-make-once-hook`, `cj/--f4-dispatch`, `cj/--f4-compile-and-run-impl`, `cj/--f4-clean-rebuild-impl`, `cj/--f4-project-root`) plus three thin interactive wrappers. Smoke tests confirm bindings register on load.

Known limitation: if another `compilation-finish-functions` hook fires between my add-hook and the compile finishing, the chain can fire on the wrong compile. The hook self-removes on first invocation regardless of which compile it sees. Documented in the impl docstring. Acceptable for v1.

Phase 2 will replace F6 with the polyglot test runner (tree-sitter queries for Python/Go/TS, sexp scan for Elisp, buffer-local last-test memory).

1 files changed, 118 insertions, 0 deletions

diff --git a/tests/test-dev-fkeys--f4-clean-rebuild-impl.el b/tests/test-dev-fkeys--f4-clean-rebuild-impl.el
new file mode 100644
index 00000000..27c7c56a
--- /dev/null
+++ b/tests/test-dev-fkeys--f4-clean-rebuild-impl.el
@@ -0,0 +1,118 @@
+;;; test-dev-fkeys--f4-clean-rebuild-impl.el --- Tests for cj/--f4-clean-rebuild-impl -*- lexical-binding: t -*-
+
+;;; Commentary:
+;; Tests for the "Clean + Rebuild" action handler. Runs the heuristic clean
+;; command via `compile' from the project root, then chains
+;; `projectile-compile-project' on success via the one-shot finish hook.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'dev-fkeys)
+
+(defmacro test-dev-fkeys-cr--with-project (markers &rest body)
+  "Create a temp project dir with each filename in MARKERS as an empty file.
+Bind the dir path to ROOT in BODY. Cleans up on exit."
+  (declare (indent 1))
+  `(let ((root (make-temp-file "test-dev-fkeys-cr-" t)))
+     (unwind-protect
+         (progn
+           (dolist (marker ,markers)
+             (write-region "" nil (expand-file-name marker root)))
+           ,@body)
+       (delete-directory root t))))
+
+;;; Normal Cases
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-runs-derived-clean-cmd ()
+  "Normal: handler invokes `compile' with the heuristic clean command for the
+project marker present at ROOT.
+
+Components integrated:
+- `cj/--f4-clean-rebuild-impl' (unit under test)
+- `cj/--f4-derive-clean-cmd' (real)
+- `compile' (MOCKED — captures the command string)
+- `projectile-compile-project' (MOCKED — no-op)
+- `compilation-finish-functions' (real, scoped via let)"
+  (test-dev-fkeys-cr--with-project '("Makefile")
+    (let ((compile-calls nil)
+          (compilation-finish-functions nil))
+      (cl-letf (((symbol-function 'compile)
+                 (lambda (cmd) (push cmd compile-calls)))
+                ((symbol-function 'projectile-compile-project)
+                 (lambda (_arg) nil)))
+        (cj/--f4-clean-rebuild-impl root)
+        (should (equal compile-calls '("make clean")))))))
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-installs-finish-hook ()
+  "Normal: handler installs exactly one hook in `compilation-finish-functions'."
+  (test-dev-fkeys-cr--with-project '("go.mod")
+    (let ((compilation-finish-functions nil))
+      (cl-letf (((symbol-function 'compile) (lambda (_cmd) nil))
+                ((symbol-function 'projectile-compile-project)
+                 (lambda (_arg) nil)))
+        (cj/--f4-clean-rebuild-impl root)
+        (should (= (length compilation-finish-functions) 1))))))
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-hook-runs-projectile-compile-on-success ()
+  "Normal: when the clean step finishes successfully, the installed hook
+calls `projectile-compile-project' to do the rebuild."
+  (test-dev-fkeys-cr--with-project '("Cargo.toml")
+    (let ((compile-calls 0)
+          (compilation-finish-functions nil))
+      (cl-letf (((symbol-function 'compile) (lambda (_cmd) nil))
+                ((symbol-function 'projectile-compile-project)
+                 (lambda (_arg) (cl-incf compile-calls))))
+        (cj/--f4-clean-rebuild-impl root)
+        (run-hook-with-args 'compilation-finish-functions nil "finished\n")
+        (should (= compile-calls 1))))))
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-runs-clean-from-project-root ()
+  "Normal: the clean compile runs with default-directory bound to ROOT."
+  (test-dev-fkeys-cr--with-project '("Eask")
+    (let ((seen-dir nil)
+          (compilation-finish-functions nil))
+      (cl-letf (((symbol-function 'compile)
+                 (lambda (_cmd) (setq seen-dir default-directory)))
+                ((symbol-function 'projectile-compile-project)
+                 (lambda (_arg) nil)))
+        (cj/--f4-clean-rebuild-impl root)
+        (should (string= (file-name-as-directory seen-dir)
+                         (file-name-as-directory root)))))))
+
+;;; Boundary Cases
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-hook-skips-rebuild-on-failure ()
+  "Boundary: when the clean step fails, projectile-compile-project does not run."
+  (test-dev-fkeys-cr--with-project '("Makefile")
+    (let ((compile-calls 0)
+          (compilation-finish-functions nil))
+      (cl-letf (((symbol-function 'compile) (lambda (_cmd) nil))
+                ((symbol-function 'projectile-compile-project)
+                 (lambda (_arg) (cl-incf compile-calls))))
+        (cj/--f4-clean-rebuild-impl root)
+        (run-hook-with-args 'compilation-finish-functions nil "exited abnormally\n")
+        (should (= compile-calls 0))))))
+
+;;; Error Cases
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-no-clean-cmd-signals-user-error ()
+  "Error: a project root with no recognized markers signals a user-error
+rather than silently running nothing."
+  (test-dev-fkeys-cr--with-project '("README.md")
+    (cl-letf (((symbol-function 'compile) (lambda (_cmd) nil))
+              ((symbol-function 'projectile-compile-project)
+               (lambda (_arg) nil)))
+      (should-error (cj/--f4-clean-rebuild-impl root) :type 'user-error))))
+
+(ert-deftest test-dev-fkeys-clean-rebuild-impl-nil-root-signals-user-error ()
+  "Error: a nil root signals a user-error (no project detected)."
+  (cl-letf (((symbol-function 'compile) (lambda (_cmd) nil))
+            ((symbol-function 'projectile-compile-project)
+             (lambda (_arg) nil)))
+    (should-error (cj/--f4-clean-rebuild-impl nil) :type 'user-error)))
+
+(provide 'test-dev-fkeys--f4-clean-rebuild-impl)
+;;; test-dev-fkeys--f4-clean-rebuild-impl.el ends here